Chain-tightening means with ratchet lock



0d. 7, 1952 N E S 2,612,988

CHAIN-TIGHTENING MEANS WITH RATCHET LOCK Filed Jan. 14, 1950 98 w F7613 8O 88 9:4 80 32 L76. 4

37? 34 r ga E i" 2 40 1 42 1 66 ,,--42 as 4 94' as I \\L\\ \v m 62 w INVENTOR. NORMAN F. ANDREWS Patented ca. 7, 1952 CHAIN-TIGHTENING MEANS WITH RATCHET LOCK Norman F. Andrews, Ankeny, Iowa, assignor to Deere Manufacturing 00., Dubuque, Iowa, a

corporation of Iowa Application January 14, 1950, Serial No. 138,655

13 Claims. (Cl. 198--208) This invention relates to a chain-tightening means and more particularly to such means embodying biasing means for normally urging a pair of relatively movable parts in chain-tightening direction and having a pair of ratcheting lock members for preventing retrograde movement of the parts.

The invention is designed primarily for use in a corn harvester or the like having a'gathering unit including a support on which is mounted one or more endless chains utilized for the purpose of gathering crops such as standing corn stalks. In a machine of this type, the gathering chains operate in planes inclining upwardly and rearwardly as respects the direction of travel of the machine and ordinarily include paddles or lugs for engaging the stalks and moving them rearwardly into a stalk-receiving throat or passage. It is conventional to provide adjustments for these chains so that the tension thereon may be maintained uniform. However, in such conventional constructions uniformity of tension is achieved only at the expense of constant attention to the adjustment. It is known in some instances to provide spring-loaded meansto maintain tension at all times on the chain. However,'this means is yieldable under stress and a portion of the chain may become sufficiently loose as to cause the chain to be thrown from its carrying sprocket. According to the present invention, these disadvantages are eliminatedby providing a chain tightener that is spring-loaded in a chain-tightening direction and which has cooperative lock members provided respectively with interengageable portions constructed to permit one-way-overrunning movement of a movable member relative to a fixed member and to prevent retrograde or opposite relative movement of the members.

A further object of the invention is to provide an improved chain tightener that is simple and inexpensive in construction and one that is efiicient and has long life in operation. Astill further object is to provide means for selectively disengaging the lock members so that inward or retrograde movement of the chain-carrying members may be had when desired. It is an: other object of the invention to provide a chain tightener having a carrier including a tubular guide within which is carried a tubular slide, and to provide a compression spring within the guide and slide and acting between the two so as to accomplish the purposes set forth above, the arrangement "of the guide and slide being such that the spring is at all times completely enclosed.

Specifically, it is another object to provide the lock members within the tubular construction in such manner that they are likewise enclosed. Thus the functional parts of the chain tightener to as great an extent as possible are protected against the entrance of dirt and other foreign matter, which is important in the application of the invention to a harvester of the type re-' ferred to, since the chain tightener is normally located close to the ground and is thereby in a position in which it is subjected to extremely dirty and trashy conditions.

The foregoing and other important objects and desirable features inherent in and encompassed by the invention will become apparent as a preferred embodiment of the inventionis completely disclosed in the following detailed description and accompanying sheet of drawings in which Figure l is a fragmentary plan view of a portion of the gathering unit of a corn harvester having a gathering chain carried in part by the improved chain tightener;

Figure 2 is an enlarged longitudinal sectional view taken substantially along the line 2-2 of; Figure l; 3

Figure 3 is a transverse sectional view taken on the line 3-3 of Figure 2;

Figure 4 is a transverse fragmentary sectional view taken on the line 4-4 of Figure 2; and

Figure '5 is a fragmentary sectional view taken on the line 5-5 of Figure 2.

That portion of the corn harvester illustrated in Figure l is a forward portion embodying a crop-gathering unit including a longitudinally extending support Ill connected in any appropriate manner at its rear end to harvester structure including a gear casing 12. An elongated endless gathering chain M has opposite or front and rear end loops [6 and I8 trained respectively about rotatable means in the form of sprockets 20 and 22 carried respectively at front and rear portions of the support ill. The sprocket 22 is carried by a vertical driven shaft 24 which ex tends from the gear case l2.

The chain operates in the direction of the arrow A in Figure 1 so that the inner longitudinal flight thereof passes over or adjacent a longi-, tudinally extending snapping roll 26. This roll is rotatablein the direction of the arrow B in Figure 1 and is driven by a second shaft 28 projecting forwardly from the gear casing [2. In the conventional corn harvester of the picker type there are a pair of snapping rolls arranged side by side to provide a longitudinal stalk-receiving passage into which stalks are urged by a plurality of gath ering chains similar to the chain 14. Since these details of harvester construction are generally conventional and well known, only such portion thereof has been illustrated in Figure 1 as is necessary to serve as orientation for the disclosure of the present invention. A typical corn-harvester construction of the type referred to may be found in U. S. Patent No. Reissue 23,083.

The chain tightener embodied in the present invention provides means for maintaining a uniform tension on the chain l4 through the use of biasing means to urge the sprocket 20 constantly forwardly. As will be hereinafter brought out in greater detail, the chain tightener includes means for preventing retrograde movement of the sprocket 20 so that, normally, the chain will not become loose or slack through wear or temporary overloading.

The chain tightener comprises essentially a carrier designated generally by the numeral 30 which is preferably in the form of an elongated plate structure 32 having opposite upturned flanges 34. The plate has arelatively flat bot tomor underside 36 beneath which is disposed a second carrier part 38 of U shape in cross section and having lengthwise attaching flanges 40 that are secured to the underside of the plate 32 as by means of a plurality of bolt and nut assemblies 42 which assemblies are here shown as representative of means for affixing the carrier parts to the support l0 As best shown in Eigures 2 and ,the; relationship of the parts comprising the plate 32-ancl U-shapedpart 38 constitutes an elongated tubular guide within which is carried means providing an elongated slide 44.

This slide is likewise preferably tubular and has front and rear end portions 46 and 48 the latter being slidably carried in the tubular guide. The front end projects forwardly beyond the front end of the-tubular guide and carries means for supporting the chain M. In this instance, the means comprisesa vertical spindle or hearing member 50 for journaling the Spr cket 20. The upper end of the spindle 50 is threaded to re- QciYea nut 52,. and the .p ate 32 i 'formed W an elongated slot 54 to allow longitudinal movement of the nut 52 as the slide moves in the guide. Opposite side wallportions of the tubular structure of the slide 44 are slotted or cut out as at 56 to accommodate the sprocket 20. Opposite side walls of the tubular structure providing the guide part 38 arecut out as at 58 (dotted lines in Figure 2) for the same purpose.

The forward end of the guide 38 is open so that the slide 44- may project therethrough. The rear end of the guide 38 is provided with closuremeans constituting an abutment 60 (Figures 2 and 5) for receiving one end of biasing means in the form of an elongated compression spring 62. The other end of the spring 62 seats against a second abutment 64 rigidly carried within the slide 44 just rearwardly of the sprocket 20. The spring 62 operates normally to urge the slide forwardly so that tension is always maintained on the chain [4.

A further feature of th invention resides in the means for permitting forward extension of the slide 44 while operating to prevent retrograde or rearward movement of the slide. For this purpose, the guide and slide respectively carry lock members 66 and 68. The lock member .68 is preferably in the form of arectangular plate rigidly secured as by welding at m to the top wall of the slide 44. The upper surface of the plate 68 is transversely notched or serrated, as at 12.

For the purpose of accommodating the plate 68, the rear portion of the plate 32 is depressed or deformed upwardly, as at 14, to provide a longitudinal space 16 within which :the plate 68 may move as the plate is carried *back and forth by the slide 44. The forward part of the deformation 14 includes a wall portion 18 which, in cooperation with the forward or leading portion of the plate 68, provides stop means for limiting forward travel of the guide 38.

The deformation at 14 is continued upwardly into a hat, section at 8!! which provides a chamber 82. within which is housed a portion of the lock member 56. As best shown in Figures 2 and 4, this member comprises a lower portion 84 presenting a substantially rectangular area which is serrated at 86 for cooperation with the serrations 12 on the plate 68. The member 66 further includes an upstandingportion 88 which projects upwardly and outwardly through an opening 90 in the top wall of the hat sectionBD. Yieldable means in the form of a light compres-. sion spring 92 seats at one end against the under surface of the top Wall of the hat section 8|] and at its other end in a substantially annularwgroove or pocket 94 in the member 66, and operates nor-. mally to urge the lock member 66 into en a ement with the lock member 68. The serrated portions of the two members are cooperativeto establish interengageable, one-way-overrunning portions arranged to provide for movement of'the slide outwardly-under action of the compression spring 62 and for locking upon attempted inward or retrograde movement of the slide relative to the guide.

A further feature of the inventionresides in means including a movable element selectively operative to disablethe lock member-66 so thatlit is prevented from engaging the lock member 68. As best seen in Figures 2 and 3, the vertical por-' tion 88 of the member that projects outwardlythrough the opening 9,0 in the 'top wall of the hat section has a transverse pin 96 onywhich is pivotally carried a releaseor cam element 198. When the element is in the position shownzin Figure 2, the spring 92 is capable of urging the member 66 into engagement with the member 63. However, when the element 98 is moved in a counterclockwise direction about the'pin.96,:.the member 66 will be withdrawn upwardly and out of engagement with the; member 68. whenrthe members 66 and 68 are disengaged, the slide, 44 may be moved inwardly of the guide 38 against, the action of the spring 62, as when itisdesired to remove thechain l4.

A further feature of the invention resides in the provision of cooperative portionson theguide and slide which are positioned for alinement when the slide is moved a predetermined extent into the guide. For this purpose, the plate 32 has an intermediate portion thereof provided with an opening or aperture I00 and the top wall of the tubular slide structure 44 is provided with a similar hole or aperture I02. During normal operation of the chain tightener, alinementv or misalinement of the openings I00 and I02 is unimportant. However, when it'is desired to .remove the chain M or to make other repairs in the gathering unit requiring relaxation of the chain I4, the lock membersBG and 68 may be disabled bymeans of the element .98, whereupon the slide 44 may be moved manually inwardly againstithe spring 62 until the opening I02 becomesalined with the opening I00. A .punch or other suitable tool or implementmay then be inserted through i the gap established by the alined openings I00. and I02 to temporarily retain the slide'against outward movement. This tool is, of course, to be removed before the chain tightener can function normally.

Various features of the invention not specifical- 1y enumerated above will undoubtedly occur to those versed'in the art, as likewise will numerous modifications and alterations in the preferred embodiment disclosed, all of which may be achieved without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. For a crop harvester having gathering mechanism including a support, an endless crop moving chain disposed in elongated looped form over the support and having opposite end loops,'and rotatable means mounted on the support and carrying one end loop of the chain, the improvement residing in adjustable mechanism for mounting on the support to carry the other looped end of the chain in spaced relation to the rotatable means, comprising: a carrier having means for affixation to the support at a portion of the support spaced lengthwise of the chain from the rotatable means, said carrier including a tubular guide extending lengthwise as respects the chain and having an open end remote from the rotatable means, and including means closing its opposite end; a slide means carried by the guide for movement lengthwise thereof and having an inner end portion within the guide and further having an outer end por tion projecting lengthwise outwardly of the open end of the guide; biasing means within the guide and acting between the inner end portion of the slide and the end-closing means of the guide to urge the slide outwardly of the guide; means on the projecting end portion of the slide for the carrying of the other looped end of the chain; a first lock member fixed to the inner end portion of the slide; means providing a chamber on the guide opening to the interior of the guide in the zone of the first lock member; a second look member movably carried by the chamber means for engagement with the first lock member; means within the chamber means normally urging the second lock member into engagement with the first lock member, said lock members having cooperative interengageable, one-wayoverrunning portions arranged to provide formovement of the slide outwardly under action of the aforesaid biasing means and for locking of the members upon attempted inward movement of the slide; and limit means cooperative between the guide and slide and separate from the chain for limiting outward movement of the guide.

2. The invention defined in claim 1, further characterized in that: the chamber means carries a movable element engageable with the second look member and selectively operative to disable the second look member, as respects its function of engaging the first lock-member, so that the slide may be moved inwardly against said biasing means.

3. The invention defined in claim 2, further characterized in that: the slide and carrier respectively have portions normally misalined but positioned for alinement when the slide is moved a predetermined extent into the guide, said portions being constructed and arranged and oooperative with each other to provide a gap to receive a tool or the like for holdingthe slide against action of said biasing means.

4. The invention defined in claim 1, further characterized in that: the limit means includes a portion on the guideand a cooperative portion on the first lockmember.

5. The invention defined in claim 4, further characterized in that: the limit portion on the guide includes a wall of the chamber means spaced to provide for limited free movement of the first lock member as it moves with the slide during outward travel of said slide, said wall having a part directed into the path of the first lock member to be engaged by said first lock member stop portion.

6. The invention defined 'in claim 1; further characterized in that: the first lock member is carried on a top portion of the slide; the tubular guide includes a top wall having a portion thereof deformed-upwardly to provide a space of such shape and length as to houseand permit lengthwise movement of the first lock member as said first lock member moves with the slide.

7. The invention defined in claim 6, further characterized in that: said portion of the guide top wall is further deformed upwardly to provide at least part of said chamber means within which the second lock member is disposed.

8. The invention defined in claim 7, further characterized in that: the carrier has a first part provided with a relatively fiat underside, and a second elongated part U-shaped in cross-section and positioned under and secured to said first part to provide said tubular guide; said underside of the first part constituting said top wall having the deformed portion.

9. The invention defined in claim 1, further characterized in that: the carrier includes a first part having a generally fiat, relatively long underside, and further includes a second elongated part U-shaped in cross-section and positioned under the first part to provide said tubular guide.

10. The invention defined in claim 9, further characterized in that: the biasing means is a relatively long compression spring; and the inner end portion istubular and of such length as to house a substantial portion of the length. of said spring to prevent exposureof said spring during maximum outward movement of the slide.

11. For a crop harvester having gathering mechanism including a support, an endless cropmoving chain disposed in elongated looped form over the support and having opposite end loops. and rotatable means mounted on the support and carrying one end loop of the chain, the improvement residing in adjustable mechanism for mounting on the support to carry the other looped end of the chain in spaced relation to the rotatable means, comprising: a carrier having means for affixation to the support at a portion of the support spaced lengthwise of the chain from the rotatable means, said carrier including a hollow guide having an open end and including abutment means at its opposite end; a slide means carried by the guide for movement through the open end of the guide and toward and away from the abutment means of the guide said slide means having an inner end portion within the guide and further having an outer end portion projecting outwardly of the open end of the guide; biasing means within the guide and acting between the inner end portion of the slide and the abutment means of the momma snide .to urge the slide outwardly of the guide;

means *on the ,;projecting end portion of. the slide for the'carryingofitheother looped end of thewchain; a. first lockmember fixedto thetinner end portion of the slide; means providing a chamber on :the guide opening to the interior of the guide in the zoneiofthe'first lockflmem'ber; a. second look member 'movably carried by the chamber means for engagement with the first lock member; and means within the chamber means-normally urging'the second lock member into engagement with .the:firs.t lock member,. said lock members having cooperative interengagable, 'one wayoverrunning portions arranged .to provide for movement of the .slide outwardly under action of the aforesaid biasing means amffor locking aof the'mem'bers upon attempted inwardrmovementiof the slide.

.12, .The invention defined in :claim 11, :further-zcharacterizedin. that: the chamber means carries: amovable elementengageable with the second. look member and selectively operative to disable the. second lock member, as respects 8 its. iunction of engaging the first Jock-member, so thatthe slide: may :be moyedinwardlyfiagainst said biasing means.

13. Theinvention defined inrclaim 112, further characterized in that: the :slide and carrier respectively have portions normallyzmisalined but positioned for alinement when the slide is moved a predetermined extentinto the guide. saidlportions being constructed and arranged and -cooperative "with each "other to provide a eap to receive a tool-or the like for holding the slide against action of said bi'asing means.

NORMAN ANDREWS.

REFERENCE S GIT ED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 829,091 Stone Aug. 21, .1906 l,405,885 Woodson .....7 Feb. .7, 11922 

